I single hand a 22,000 lb 42 foot Catalina sloop. As someone mentioned above, its all about the last 5 feet to the dock. I did not purchase this boat with the intent of single hand live aboard cruising. I might have purchased something a bit smaller to reduce the physical effort of sail handling. However, in adverse conditions you generally are working to reduce sail, much easier than putting sail up. Also, as a cruiser I don't do "racing" changes. If it takes 15 minutes to raise the main, with appropriate rests in between cranking, so be it. That is all good.

What is difficult to control is the last 5 feet to a dock by yourself under adverse conditions. With a heavy boat you can not muscle it. You have to sail/motor it into the dock. Amateurs use bow and stern lines, the initiated use spring lines. A spring with a big loop on the dock end that can be hooked over a cleat gets that very important first attachment without ramming the bow or the stern into the dock or having the boat stream out at a 90 degree angle to the dock.

This leads to three conclusions:
1) You can't go bigger than a size at which you are comfortable that you can handle the sheets and halyards with whatever equipment is on the boat - which could include electric winches etc. Of course anything but people power gives you the additional risk that things might fail.
2) If you have the boat handling skills it doesn't much matter how heavy the boat is when you are docking, you are using the engine and rudder to make your approaches.
3) You need to have the common sense to not sail over your head. I have chosen to anchor out rather than try to approach a dock in adverse conditions, sat in port more than once waiting for a weather window, and run from adverse conditions in the open ocean (not fun, and it usually only makes things a little less adverse, but heck, you got to do what you got to do!)